The　natural　ventilation　of　the　light　pipe　system　was　simulated　by　the　CFD　method.　The　effects　of　different　factors,　including　velocity　and　directions　of　the　outdoor　wind,　the　construction　of　the　terminals,　the　length　of　the　ventilation　pipe,　the　space　between　the　two　coaxial　pipe　and　the　diameter　of　the　light　pipe　on　the　natural　ventilation,　was　studied.　The　results　shown　that　the　H　type　terminal　has　the　high　natural　ventilation　effect,　and　there　exists　the　minimal　ventilation　volume　which　vary　with　the　length　of　the　ventilation　pipe　and　the　space　between　the　two　coaxial　pipe,　and　the　ventilation　volume　increased　with　the　increasing　of　diameter　of　light　pipe.　Those　results　can　provide　an　theoretic　instruction　for　the　application　of　the　light　pipe　system.